This invention relates to a method for the analysis of one or more buried layers of an analyte material by: a) removing one or more surface layers of said analyte material with an atomic force microscopy (AFM) stylus to expose a buried layer; and b) analyzing the buried layer.
Methods are known for analysis of thin buried layers in a material sample which involve removal of a surface layer by chemical means, or means which cause chemical alteration in the sample. While such methods may be useful for elemental analysis, they are of very limited use for molecular analysis since they inherently involve alteration of molecular structure. One such method is sputtering, wherein the sample is treated with an ion beam in the kilovolt energy range. Since sputtering breaks intramolecular chemical bonds and destroys molecular information, sputter depth profiling is typically used for elemental analysis.
Briefly, the present invention provides a method for the analysis of one or more buried layers of an analyte material by: a) removing one or more surface layers of the analyte material with an atomic force microscopy (AFM) stylus or similar stylus apparatus to expose a buried layer; and b) analyzing the buried layer by a surface analytical technique.
In another aspect, the present invention provides an apparatus combining an atomic force microscopy (AFM) device or similar stylus device and one or more additional surface analytical devices, in particular where the apparati are housed in cooperating atmosphere-controlled chambers and under cooperating computer control.
What has not been described in the art, and is provided by the present invention, is a method for molecular analysis of buried layers of an analyte material at depths of a few Angstroms up to about 300 xcexcm without chemical alteration of the material.
In this application:
xe2x80x9cburied layerxe2x80x9d includes a buried object or a segment of a buried layer or object;
xe2x80x9canalytexe2x80x9d refers to a sample of material to be analyzed; and
xe2x80x9cvacuumxe2x80x9d means, with reference to an analytical technique performed under sub-atmospheric pressures, a sub-atmospheric pressure suitable for the practice of that technique, and is preferably less than 1.3xc3x9710xe2x88x922 Pa (1xc3x9710xe2x88x924 torr), more preferably less than 1.3xc3x9710xe2x88x924 Pa (1xc3x9710xe2x88x926 torr) and even more preferably less than 1.3xc3x9710xe2x88x926 Pa (1xc3x9710xe2x88x928 torr).
It is an advantage of the present invention to provide a method and apparatus for molecular analysis of buried layers of an analyte material at depths of a few Angstroms up to about 300 xcexcm.